Despite being able to ignore many odd occurrences in the house, there are several things that will classically attract acute attention from a parent: fever; a child “not eating;” not pooping for a day; lumps and bumps; and rashes. The bathtub happens to be a common environment that the last two are first detected. Historically, physicians even used “bathtubs” to feel for intra-abdominal masses. Let us take a minute to review a significant abdominal mass that a parent may first detect with the assistance of bath time – Wilms’ Tumor:

Wilms’ Tumor: Basics

• Wilms’ Tumor (nephroblastoma) is common! [Servaes, 2019; Szychot, 2014]
  • It affects 1 in 10,000 children!
  • Accounts for ~5% of ALL childhood cancers.
  • Accounts for ~80% of all pediatric renal tumors.

• Most commonly encountered in younger children. [Servaes, 2019; Szychot, 2014]
  • 95% of cases occur in children < 10 years of age.
  • Vast majority diagnosed before age of 5.
  • It can rarely, however, occur in older patients and adults.

• A predisposing genetic syndrome is associated with ~5% of Wilms’ Tumor patients: [Szychot, 2014]
  • Several well defined genes play a role in Wilms’ Tumor like:
    • WT1 gene
    • WT2 gene
    • WTX gene
  • These can be found concurrently in other genetic syndromes:
    • WAGR syndrome (Wilms’ tumor, Aniridia, Genitourinary (GU) abnormalities, and mental Retardation)
    • Beckwith-Wiedemann syndrome
    • Denys-Drash syndrome – GU abnormalities, and nephropathy, hypertension
    • Frasier syndrome – Focal glomerular sclerosis, kidney failure, and gonadal dygenesis
    • Simpson-Golabi-Behmel syndrome
  • Children with genetic syndromes linked to Wilms’ tumor are screened routinely during your childhood.

• Overall survival is > 90%! [Servaes, 2019]
  • Unfavorable characteristics include:
    • Unfavorable histology and molecular markers
    • Bilateral disease
    • Relapse
  • Classification plays a role in management and prognosis.
    • Classification differ between Children’s Oncology Group (COG) and International Society of Pediatric Oncology (SIOP).
    • Management decisions (ex, immediate nephrectomy vs pre-surgical chemotherapy) also differ between the groups, but outcomes are similar.

Wilms’ Tumor: Presentations

• The majority of patients will present with an “asymptomatic abdominal mass.” [Szychot, 2014; Erginel, 2014]
  • Often described by parents as being found during bathing.
  • Also noted as a protuberant abdomen at times.
  • Mass is typically firm.

• ~20-30% will complain of abdominal pain. [Szychot, 2014]
  • The tumor itself can cause mass effect on other adjacent structures.
  • Tumor may not, itself, be tender on palpation.

• Other findings: [Szychot, 2014]
  • Hypertension
    • Found in ~25% of cases.
    • Usually resolves after nephrectomy.
    • Can be associated with other genetic syndromes (ex, Denys-Drash syndrome)
  • Macroscopic or Microscopic Hematuria

• Tumors may also present in ExtraRenal sites [Rojas, 2013]
  • Many case reports of Wilms’ occur outside of the kidney with no kidney involvement.
  • Can be found in:
    • Bladder
    • Inguinal area
    • Vagina
    • Ovary
    • Lumbar paraspinal area
    • Coccyx
    • Retroperitoneum

• Presentations may also be of known complications: [Szychot, 2014]
  • Uncommon (<10% of cases), but can be severe.
  • Acute Abdomen
    • Rapid tumor enlargement
    • Anemia
    • Hypertension
    • Fever
    • May have associated tumor rupture
  • Tumor Extension into adjacent vascular structures.
    • ~11% of cases involve vascular extension.
    • Thrombus also can occur – ~4%
    • Renal Vein and Inferior Vena Cava involved.
    • May lead to:
      • Congestive Heart Failure
      • Acites
      • Hepatomegaly
  • Varicocele
  • Paraneoplastic syndromes
    • Hypercalcemia
    • Erythrocytosis
    • Acquired von Willebrand disease

• Late Effects / Complications [Servaes, 2019; Szychot, 2014]
  • The “cost of cure” can be high in survivors of Wilms’ tumor.
  • Anthracycline (ex, Doxorubicin) therapy can lead to Heart Failure.
  • Pulmonary fibrosis can occur from lung radiotherapy.
  • Secondary malignant neoplasms can develop:
    • Sarcomas of bone and soft-tissue
    • Breast cancer
    • Leukemia
    • Lymphoma
    • Melanoma

Wilms’ Tumor: Initial Evaluation

• Abdominal Ultrasound is the 1st imaging modality. [Servaes, 2019; Szychot, 2014]
  • Characterizes the mass.
  • Defines the location and extent of involvement (both kidneys?).
  • Determines whether vascular invasion or clot formation is present.
  • Checks liver for metastases.

• CT and/or MRI of the abdomen [Servaes, 2019; Szychot, 2014]
  • Both are considered reasonable to use to further evaluate once renal tumor is detected.
  • MRI may be preferred if both kidneys are involved.

• Chest imaging. [Servaes, 2019; Szychot, 2014]
  • The lungs are a common site of metastatic spread.
  • 10 – 20% will have lung involvement at time of diagnosis.
  • CXR is usually the initial study performed in the ED.
  • CT will often be done as well.

Moral of the Morsel

• The Bath – a great place for parents to detect pathology!
• It isn’t constipation. A painless abdominal mass in a previously healthy child can be the presentation of Wilms’ tumor.
• Check the Ultrasound! But, don’t forget about the lungs!

References